What if your iPhone charging cable could charge your phone even when it wasn’t plugged into a charger? It’d be pretty neat, right? Well, that’s what Native Union’s Jump does, and it does it all while being the best-looking Lightning cable yet.

The secret is of course batteries, and the Jump has an 800mAh battery inside the reel that the cable wraps around. The idea is that you unwrap the cable and use it to charge the iPhone as normal (the cable also lets you sync it with iTunes) and – when the iPhone is charged – the power is redirected to charge the Jump. And while 800mAh doesn’t sound like much, it’s enough to add a quick 33%-ish boost to the iPhone.

I like that the thing is tiny and light (40 grams): if I want a big battery pack there’s plenty of choice out there, but I usually leave them at home as they’re just heavy. Having an almost unnoticeable battery built into the cable spindle itself is clever indeed.

The Jump comes in two flavors: Lightning and microUSB, and both cost $40 if you pitch in on the Kickstarter campaign, or $50 if you wait until May when the Jump is expected to ship.